Does PostgreSQL support computed / calculated columns, like MS SQL Server? I can’t find anything in the docs, but as this feature is included in many other DBMSs I thought I might be missing something. Eg: http://msdn.microsoft.com/en-us/library/ms191250.aspx Answer Up to Postgres 11 generated columns a…
Concatenate with NULL values in SQL
Column1 Column2 ——- ——- apple juice water melon banana red berry I have a table which has two columns. Column1 has a group of words and Column2 …
Deleting duplicate rows from sqlite database
I have a huge table – 36 million rows – in SQLite3. In this very large table, there are two columns: hash – text d – real Some of the rows are duplicates. That is, both hash and d have the same …
SQL: ORDER BY using a substring within a specific column… possible?
I have a database whose columns are npID, title, URL, and issue. Here is an example of two years’ entries: What I would like to do is be able to sort the results based on substrings within the “issue” column. However, until 2010, the client used seasons as the header and in 2010, they starte…
SQL Select between dates
I am running sqlite to select data between two ranges for a sales report. To select the data from between two dates I use the following statement: This statement grabs all the dates even those outside the criteria. The date format you see entered is in the same format that I get back. I’m not sure what&…
How do I find duplicates across multiple columns?
So I want to do something like this sql code below: To produce the following, (but ignore where only name or only city match, it has to be on both columns): Answer Duplicated id for pairs name and city:
Extract first numeric part of field
I have a database (Postgres 7.4) field for address Example Data The queries I get all but I don’t want 123 main street I get the results I want My question is how do I just match the numeric part of the address? Answer Returns 1 or more digits from the start of the string. Leave out the anchor ^
How to COUNT duplicate rows?
I want to be able to create a histogram out of a tuple containing two integers values. Here it is the query: For this input: Would be: How can I create a histogram of those values? In other words, how can I count how many times a row has a duplicate? Answer The question leaves room for interpretation. This te…
how to avoid duplicate on Joining two tables
This result is 2 times A even after using disticnt . My expected result will have only one A. if i remove row_number() over() as rownum its working fine. Why this is happening ? how to resolve. AM using DB2!! Answer There are two rows in marks Table with id = 1 and mark = 50.. So you will get
Know relationships between all the tables of database in SQL Server
I wish to all know how the tables in my database are related to each other (i.e PK/FK/UK) and hence i created a database diagram of all my tables in SQL Server. The diagram that was created was not easily readable and had to scroll (horizontally and sometimes vertically) to see the table on the other end. In …